A number of components on-board an aircraft require electrical power for their activation. Many of these components are separate from the electrical components that are actually required to run the aircraft (i.e., the navigation system, fuel gauges, flight controls, and hydraulic systems). For example, aircraft also have catering equipment, heating/cooling systems, lavatories, power seats, water heaters, and other components that require power as well. Specific components that may require external power include but are not limited to trash compactors (in galley and/or lavatory), ovens and warming compartments (e.g., steam ovens, convection ovens, bun warmers), optional dish washer, freezer, refrigerator, coffee and espresso makers, water heaters (for tea), air chillers and chilled compartments, galley waste disposal, heated or cooled bar carts/trolleys, surface cleaning, area heaters, cabin ventilation, independent ventilation, area or spot lights (e.g., cabin lights and/or reading lights for passenger seats), water supply, water line heating to prevent freezing, charging stations for passenger electronics, electrical sockets, vacuum generators, vacuum toilet assemblies, grey water interface valves, power seats (e.g., especially for business or first class seats), passenger entertainment units, emergency lighting, and combinations thereof. These components are important for passenger comfort and satisfaction, and many components are absolute necessities.
However, one concern with these components is their energy consumption. As discussed, galley systems for heating and cooling are among several other systems aboard the craft which simultaneously require power. Frequently, such systems require more power than can be drawn from the aircraft engines' drive generators, necessitating additional power sources, such as a kerosene-burning auxiliary power unit (APU) (or by a ground power unit if the aircraft is not yet in flight). This power consumption can be rather large, particularly for long flights with hundreds of passengers. Additionally, use of aircraft power produces noise and CO2 emissions, both of which are desirably reduced. Accordingly, it is desirable to identify ways to improve fuel efficiency and power management by providing innovative ways to power these components.
Galleys and lavatories are connected to the aircraft potable water tank, and water is required for many of the related on-board services. Water pipes connect the water tank to the water consumers. For example, coffee cannot be made, passengers cannot use the lavatories, hand-washing water is not provided, and so forth, until the the APU or electrical switch is on in order to allow water to flow. Some examples of the water consumers on-board aircraft are the steam oven, beverage maker (coffee/espresso/tea), water boiler, tap water supply, dish washer, and the toilet vacuum system. Aircraft typically carry large amounts of potable water in the potable water tanks, which is uploaded when the aircraft is on the ground. A number of water saving attempts have been made to help re-use certain types of water onboard aircraft, but it is still desirable to generate new ways to generate and/or re-use water on-board aircraft. Other systems use heat, which is also typically generated by separate units. For example, heated water is desirable for use in warming hand-washing water (and to prevent freezing of the water pipes), the ovens and warmers onboard require heat, as well as the cabin heating units.
The present inventors have thus sought new ways to generate power to run on-board components, as well as to harness beneficial by-products of that power generation for other uses on-board passenger transport vehicles, such as aircraft.
The relatively new technology of fuel cells provides a promising cleaner and quieter means to supplement energy sources already aboard aircrafts. A fuel cell has several outputs in addition to electrical power, and these other outputs often are not utilized. Fuel cell systems combine a fuel source of compressed hydrogen with oxygen in the air to produce electrical and thermal power as a main product. Water and Oxygen Depleted Air (ODA) are produced as by-products, which are far less harmful than CO2 emissions from current aircraft power generation processes.
Turning from this broad overview of aircraft systems as a whole in order to further address details of a specific component, one particular aircraft component of interest is trolleys. In commercial passenger crafts, and particularly in passenger aircrafts, trolleys are often used by the cabin crew to serve refreshments of food and drinks to the passengers. One way to utilize the trolleys for this purpose would be to store the refreshments in a central repository on the craft before embarkation and then transfer the refreshments to the trolleys for distribution to the passengers. However, to save space aboard the craft and improve efficiency of the cabin crew, the refreshments are usually pre-loaded into the trolleys before the flight or voyage. The trolleys are then stored in or nearby the galley, where any needed further preparations to the refreshments may be completed during the trip.
Often the refreshments are to be served either heated or chilled. This can cause several issues in addition to the energy consumption concerns discussed above. For chilled items, the fact that the refreshments are pre-loaded onto the trolley normally requires the entire trolley to be placed in a chilled compartment. This limits the flexibility of the galley and the trolley because a trolley that needs to be chilled must be stored in a location with a chiller facility. In current galleys, the chiller installation also causes additional noise, which is inconvenient for the passengers directly next to the galley.
For heated refreshments, the items generally must first be taken out of a chilled trolley, then put in a steam oven or other warming apparatus, and finally placed back into a trolley after being heated. This transferring, waiting for warming to finish, and transferring again consumes substantial amounts of the cabin crew's time to prepare meals during the voyage.
Additionally, galleys are bulky monuments, requiring a substantial amount of room aboard a craft. Their common location near the front of an aircraft cabin frequently necessitates that all passengers must walk through the galley while boarding the craft. This is problematic because the galley is intended for cabin crew use only and ideally should be maintained as a restricted area. Furthermore, it presents a bottle neck that impedes quick boarding.